Lifting-jack



(N Model.)

Patented Feb;v 6, 1888-.

.xL!!!wllLllnllIyllxLhLLLl UNITED STATES' PATENT OFFICE.

JACOB O. JOYCE, OF DAYTON, OHIO.

LlFTlNG-JACK.

SPECIFICATION forming part of Letters Patent No. 271,863, dated February 6, 1883.

Application nieu August e5, 1832. (No model i To aLL whom it may concern: p

Be it known that I, JACOB O. JOYCE, a citi zen of the United States, and a resident of the city of Dayton, in the county of Montgomery and State of Ohio, have invented certainnew and useful Improvements in Lifting-Jacks, of which the following is a specification. i

My invention relates to an improvement in lever-jacks. v

The object of my invention is to provide a powerful and durable lever-jack.

Another object of my invention is to so construct a leverjaclr employing many toothed lifting and holding pawls that a tripping dez vice can be readily applied to suddenly throw out the holding-paw] and drop the lifting-bar, all ot' which will be explained in the description of the construction and operation of my improvement, which is illustrated in the annexed drawings, in which- Figure 1 represents a vertical central sectional -view of Aa lever-jackfrconstructed in accordance with my invention Fig. 2, abroken view similar to Fig. 1, showing a modification of the invention, the rack-bar being elevated; F1g. 3, a'transverse sectional view on the line a' a: of Fig. 1; and Fig. 4 is a perspective view of the-tripblock.

A represents the base of the jack; B, the upright frame; O, the rack-bar; I), the holding# pawl, which is preferably constructed as shown in my former Letters Patent No. 154,989, granted'me lSeptember' 15, 1874.

E represents the slotted opening in the upper part of the frame, in which the pawls and lever operate to engage with the rack-bar. F represents a stud-link on which the lever G hinges, so as to allow it to be moved in and out to operatethe rack-bar. lg g represent forks forming the inner end of lever Gr, and between which link F are pivoted. Lever G is moved out or ,in bythe oscillation of` stud F on its fulcra near the bottom of opening E.

I represents a trip-block, which is employed to trip the jack. It is shown in position for tripping in Fig. 2, the shoulder t' resting on the lifting-pawl H, and the top engaging with the bottom of the holding-'pawl D. When lever Gr is raised pawl D slides upward in its boXout of mesh with the teeth of rack-bar C, which drops and lowers the load. By pivoting the lever G on the stud-linkF, and pivoting the parts in the free openingE of the frame, a sufficient movement of the lever G is obtained to carry it, with the suspended pawl H, backward and upward far enough from the rack-bar O to allow ofthe ready insertion or removal of the trip-block I.

1. In a lever-jack, the lever G,hnged to the stud-link F, within the opening E of the frame of the jack, substantially as herein set forth.

2. In a lever-jack having the lever Gr hinged to the stud-link F, within the openingE in the frame of. the jack, the lifting-pawl H and `rackbar O, substantially as herein set forth.

3. In combination with the holding-pawlD and lifting-pawl H, pivoted to the Swingin g 1ever Gr, the trip-block I, adapted to engage between the pawls,'substantially as herein setV forth.

In testimony whereof I have hereunto set my `hand in the presence of two subscribing witnesses.

JAooB o. JOYCE.

'Witnesses JOHN L. H. FRANK, THos. II. GRIDLAND. 

